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Discussion Starter · #1 ·
With SKS on, as I approach the car, I hear a buzz/whirr that lasts several seconds. What is the "Welcome Buzz"? The storage thermos dumping into the block? Why does it do this before I've even unlocked the car? Nice to know the car gets a contact buzz from my company (a mutual feeling), but WTF is it?
 

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The thermos sound should only occur once the car is in READY (might occur in Ig-On, haven't thoroughly checked) or once the car is powered down. Sounds like a servo in operation.

The buzzing and hissing is the brake system equalizing. I have never heard it while approaching the car, but it does occur about 5 minutes or so after the car is turned off, and might occur occasionally after that.

The brake system operates by a pump creating brake pressure, and valves at each wheel controlled by the skid ECU to add or remove brake pressure at each wheel. The hissing I believe is the pressure being released, and the buzz is the compressor re-establishing pressure. I suppose this helps purge air that might be in the system.

I have also heard a faint whine a few times. I believe that might be the AC refrigerant settling.
 

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Discussion Starter · #3 ·
Dan, thinking about it now, it sounds kinda like the brake pump, but louder since it is outside the car. Perhaps it pumps up the brakes so you can hold the car while starting and shifting, and with SKS, it anticipates your entry when you get c
lose (like when it brings up the dome lights). Otherwise, might you have no brakes (save for the HARD push you would use with a brake failure)?
 

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KTPhil said:
With SKS on, as I approach the car, I hear a buzz/whirr that lasts several seconds.
I don't hear any kind of a buzz when I approach my 04. I hear a brief buzz when I step on the brake pedal when starting the car, but that’s normal. About the only sound I hear when approaching the car, is someone asking, “Is that a hybrid?”
 

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I hear these buzzing noises too. I was thinking that it was the Prius moving the warm coolant out of the thermos. I think that it is great that it does this before I start the car but I think that it is wasteful when it does it when I just open the door to get my sunglasses. I wish there was a way to tell that car that I'm not going anywhere, gust getting something out of the car.

Roger
 

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I was wondeirng about this myself. It doesn't appear to happen everytime, but I noticed it this morning when I approached the car. The car had been sitting for 12+ hours (overnight) so I can't imagine it was the thermos... Hmmm weird.

--GD
 
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